Composting is a natural process where kitchen and yard wastes decompose into a dark, nutrient-rich, earth-smelling soil conditioner. Perhaps you’ve considered backyard composting but live in a high rise or don’t relish the thought of tramping through your garden in the middle of a winter blizzard. If so, worm composting is the option for you.

What is worm composting?

Worm composting is simply composting with worms. The best kind of earthworm to use is an Eisenia foetida, or a Lumbricus rubellus, commonly called redworm. These worms are incredible garbage eaters! They eat and expel their own weight every day; even a small bin of redworms will yield pounds of rich sweet-smelling compost. Finished compost can be harvested in as little as two to three months. Redworms (aka “red wigglers”) are extremely prolific. It takes about three weeks for fertilized eggs to develop in a cocoon from which two or more young worms can hatch. In three months the worms are sexually mature and will start breeding. Within a year you’ll be able to give worms away to get a friend started!

Where can I get a worm bin?

For 1 or 2 people a plastic storage bin can be purchased from a hardware store. Make sure the bin has a lid. For 4 to 6 people, a design sheet to build your own bin from wood is attached (see “Building a worm compost bin.”)

# People Quantity of Worms Bin Size
1 or 2 1 lb. 1ft x 1.5ft x 2ft
2 or 3 1 lb. 1ft x 2ft x 2ft
4 to 6 2 to 3 lbs. 1ft x 2ft x 3.5 ft

How do I set up the bin?

For the plastic bin, drill 8-10 holes (approx. 1/4”) in the bottom of the bin for adequate drainage. Drill 4-6 in the lid. Line the bottom with fine nylon mesh to prevent the worms from escaping. Raise up the bin on some type of blocks with a tray underneath. After the bin is constructed you need to think about bedding for the worms. Redworms can survive and breed in many kinds of bedding materials. The “red wiggler” is a manure worm and will eat its own bedding. Materials such as fall leaves (best if shredded), shredded newspaper (hand shred into long thin strips), ground cardboard, aged animal manure, or organic peat moss can all be used. (Make sure to mix peat moss with other bedding as it is too acidic to use alone.) It is important to keep the bedding as moist as a well-wrung sponge. Since a worm’s body is made up of about 75% water it is important to be sure that the bedding is prepared with the same 75% moisture content, this will allow the worm to breathe. Using a mixing container, put in about one-half of the bedding and one-half of the water required, mix. Add two handfuls of soil and what is left of the bedding and water and mix again until the bedding is moist enough. Dump entire mixture into the worm bin. Now it is time to add the worms, dump the whole container of worms onto the bedding and spread around. Garbage may be buried as soon as the worms are in the bedding.

Where can I get Redworms?

As stated previously, redworms should be used in composting. This type of worm is most efficient because its natural environment is decaying matter, they will be able to process this organic material quickly. This special worm may be shipped through a delivery service.

Redworms can be ordered from the following suppliers and outlets:

Ryan Heberle
3815, Rt. 96
RD #2
Shortsville, NY 14548
(716) 289-4708
Cape Cod Worm Farm
30 Center Ave.
Buzzards Bay, MA 02532
(508) 759-5664
Commonwealth Wormery
PO Box N122
Westport, MA 02790
Wendy Henderson
(508) 636-8981
The Green Planet*
57 Lincoln St
Newton Highlands,
MA 02161
(617) 332- 7841
Mary Appelhof*
Flowerfield Enterprises
10332 Shaver Rd.
Kalamazoo, MI 49002
(616) 327- 0108
Beaver River Associates*
P.O. Box 94
W. Kingston, RI 02892
Josh Nelson
(401) 782-8747

In nature, redworms can be found in decaying leaves, manure piles or other organic material, such as compost piles. If you have access to such areas, you can collect your own redworms. A few handfuls are enough to start a bin, but add only small amounts of food scraps until the worm population increases enough to handle more (3-4 months).

*The above vendors offer several types of commercial worm bins and “worm kits” currently on the market, in addition to classroom curricula on worm composting. A “worm kit” includes a bin, worms, and accessories.

What do I feed them?

Worms will eat just about any type of kitchen waste including vegetables, fruits, coffee grinds, tea bags and eggshells (crushed.) Do not add meat or meat byproducts. Bury the food scraps completely, so that they are always covered by bedding; this prevents development of odors and fruit flies. Don’t add more food scraps than the worms eat in several days. The worms can’t eat the food until it starts to decompose, so it may take a few months for the bin to get up to speed. For fastest decomposition, chop the food scraps into small pieces.

The ecology of a worm bin.

The decaying materials in a compost pile may attract some critters, other than the redworms. This is a common situation and is not a bad thing as many may see it. Since these other bugs do play a role in breaking down the organic matter found in the compost bin, they are actually helping the process. Some of these organisms include centipedes, millipedes, mites, fruit flies, ants, and some others.

Can worms live outside during colder months?

 Worms prefer temperatures between 40 and 80 degrees Fahrenheit. If you live in an apartment building they can live quite happily out on the balcony until temperatures drop to 40 degrees. After that they should be taken indoors. Basements or garages that don’t freeze are good locations for worm bins.

How can I harvest the finished compost?

After about 3 months you’ll notice that the volume of materials has dropped substantially and the original bedding is no longer recognizable. At this point the finished compost and worms can be moved over to one side of the bin and now bedding added to the vacant side.

• Put new food waste into the fresh bedding only so the worms will move from the finished compost in search of new food.

• After two weeks or so remove the lid under a bright light source.

• Scoop out the finished compost a few layers at a time and place in a plastic bag, or bucket, until you’re ready to use it.

How can I use the finished compost?

Vermicompost will provide nutrients to your plants and will help the soil hold moisture. The compost created contains humus, decomposing matter, and worm castings. The mixture is often used as a dressing during the spring, but can also be used later. The ending material will be dark, crumbly, and earthy-smelling. A few chunks may be recognized as food waste or bedding, but when it is dried it will be a smooth, dark mixture. It can be used in a number of different ways:

1 - Sprinkle into a seed row when planting.

2 - When transplanting, add a handful of soil to the hole you have dug for the plant.

3 - Use as a top dressing, sprinkling the compost around the base of your plants.

4 - Mix with potting soil (half-and-half) for house plants.


Problem: Worm die-off or escaping worms

If you notice the worm population dwindling, or worms crawling all over the bin trying to escape, check for the following:

Bin is too wet and worms are drowning. Add dry bedding, increase airflow in the bin creating ventilation holes, or leaving the lid off for a while.

Bin is too dry and worms dry out. Moisten bedding. Place a strip of plastic over the bedding to retain moisture.

Only castings left in bin. Once the worms devour all of their food and bedding, they will start to eat their own castings, which are poisonous to them. Time to harvest and add fresh bedding.

The bin is exposed to extreme temperatures. The bin should not be exposed to temperatures above 77° F or below 50° F. The worms thrive in temperatures from 50 to 77 degrees F.

NOTE: Dead worms decompose rather quickly. If you do not monitor the above conditions you can have a dead box of worms before you even realize it.

Problem: Odor

If your worm bin has an unpleasant odor, one of the following may be the culprit:

Bin is too wet. Do not add any water or foods with a high percentage of water (e.g., melons,) do add more dry bedding.

Bin does not get enough air. Anaerobic bacteria (bacteria which thrives without air) is smelly. To aerate, add fresh bedding and mix bin contents daily.

The food waste is naturally smelly. For instance, we have found that onions and broccoli do not smell very pleasant when they decompose in the worm bin. Simply remove any food source that smells bad from the bin.

Bin contains non-compostables. Meat, bones, dairy and oily products should not be fed to the worms because these items become rancid when decomposing.

Problem: Fruit Flies

If you’ve found fruit flies living around and in your worm bin, you may get rid of them using one or both of the following methods:

Make a trap. Place ½ cup of beer or honey in a jar. Poke a hole in the corner of the a sandwich bag with a pen. Tighten the bag around the rim of the jar with a rubber band. The open bag should be above the level of the contents of the jar. The flies are attracted to the beer or honey and find their way in, but not their way out!

Vacuum them. When you open the lid you will see fruit flies crawling and flying about. Quickly vacuum the crawling flies and those that land nearby.


Worms Eat My Garbage, Mary Appelhof, Flower Press, Michigan, 1982, 100 pp. Available from:

  COMPOST ONTARIO, Recycling Council of Ontario
  489 College St.,Suite 504
  Toronto, Ontario M6G 1A5

Bonhotal, Jean. Kransny, Marianne E. Composting: Wastes to Resources. Cornell Coopertive Extension, Ithaca, New York. 1994